S95 - Supervision of Fire Alarm System Supervisory and Trouble Signals Questions and Answers 1 — Questions and Answers
Question 1: A building's Fire Alarm Control Panel (FACP) indicates a 'Ground Fault' condition. According to NFPA 72, which type of signal is this, and what is the implication?
- A supervisory signal, indicating a problem with a monitored system like a sprinkler valve.
- An alarm signal, indicating an immediate life-threatening emergency.
- A trouble signal, indicating a fault within the fire alarm system's wiring or components. (Correct answer)
- A pre-alarm signal, indicating that a detector has reached a set threshold below a full alarm.
Correct answer: A trouble signal, indicating a fault within the fire alarm system's wiring or components.
A 'Ground Fault' is an unwanted connection between a system conductor and ground, which indicates a wiring problem within the fire alarm system itself. NFPA 72 defines this as a 'trouble' condition, as it signifies a fault that could potentially compromise the system's ability to function correctly during an emergency. It is not a supervisory signal, which relates to the status of a separate, monitored system (e.g., a sprinkler valve), nor is it an alarm signal indicating a fire.
Question 2: An S-95 holder observes a supervisory signal on the FACP indicating 'Fire Pump Power Off'. Which of the following best describes the situation?
- The fire alarm system's backup batteries are low and require replacement.
- A fault exists in the fire alarm wiring, such as an open circuit.
- The primary power to the FACP has been lost and it is running on secondary power.
- A component critical to the building's fire suppression system is in an abnormal state. (Correct answer)
Correct answer: A component critical to the building's fire suppression system is in an abnormal state.
A supervisory signal indicates an issue with a system or equipment that the fire alarm panel monitors, rather than a fault in the fire alarm system itself. A 'Fire Pump Power Off' condition means the fire pump, a key part of the sprinkler suppression system, has lost power and is in an off-normal state that requires attention. Low batteries or wiring faults in the FACP would generate a trouble signal.
Question 3: Which of the following conditions would initiate a supervisory signal, but NOT a trouble signal?
- A tamper switch on a sprinkler control valve being closed. (Correct answer)
- A loss of primary AC power to the fire alarm control panel.
- An open circuit on a notification appliance circuit (NAC).
- A communication failure between the FACP and the central monitoring station.
Correct answer: A tamper switch on a sprinkler control valve being closed.
A supervisory signal is generated when a monitored system changes to an abnormal state. A closed tamper switch indicates that a sprinkler control valve is not in its normal open position, which impairs the suppression system. The other options—loss of AC power, an open NAC circuit, and communication failure—are all faults within the fire alarm system itself and would generate a trouble signal.
Question 4: While on duty, an S-95 certificate holder notices the FACP is beeping with a yellow light illuminated. The display reads 'Low Air Pressure - Dry Sprinkler System Zone 3'. What is the correct signal classification and the immediate priority?
- Trouble signal; the certificate holder must immediately call their service company.
- Alarm signal; the certificate holder must evacuate the building.
- Supervisory signal; the certificate holder should investigate and notify the building manager. (Correct answer)
- Pre-alarm signal; the certificate holder should wait to see if it escalates to a full alarm.
Correct answer: Supervisory signal; the certificate holder should investigate and notify the building manager.
Low air pressure in a dry sprinkler system is an 'off-normal' condition for a monitored piece of fire protection equipment. This generates a supervisory signal. It is not a trouble signal, which would indicate a fault with the FACP or its wiring. The immediate action is to investigate and inform the appropriate personnel, as it indicates a potential impairment to the fire suppression system, but not an active fire. The FDNY is not typically dispatched for supervisory signals.
Question 5: A fire alarm control panel is operating on its secondary power source (batteries) due to a building-wide power outage. After several hours, a distinct, audible signal begins to sound from the FACP, and the display shows 'Low Battery'. This signal is classified as a:
- Supervisory Signal
- Alarm Signal
- Ground Fault Signal
- Trouble Signal (Correct answer)
Correct answer: Trouble Signal
A 'Low Battery' condition indicates a fault with a critical component of the fire alarm system itself—its secondary power supply. According to NFPA 72, faults within the fire alarm system, including its power supplies, wiring, and components, are annunciated as trouble signals. This alerts personnel to a condition that could prevent the system from operating as intended in an emergency.
Question 6: What is the fundamental purpose of a supervisory signal within a fire alarm system?
- To indicate a fault, such as a broken wire or component failure, within the fire alarm system.
- To provide an early warning that a smoke detector is accumulating dust and may cause a false alarm.
- To monitor the status of other fire protection systems and indicate when they are in an abnormal state. (Correct answer)
- To initiate occupant evacuation and notify the fire department of an active fire.
Correct answer: To monitor the status of other fire protection systems and indicate when they are in an abnormal state.
The core function of a supervisory signal is to indicate that a separate but related fire protection system being monitored by the FACP is in an off-normal or compromised state. Examples include a closed sprinkler valve, fire pump power loss, or low pressure in a dry pipe system. This is distinct from a trouble signal, which points to a fault within the fire alarm system itself.
S95 - Supervision of Fire Alarm System Supervisory and Trouble Signals Questions and Answers 1
A building's Fire Alarm Control Panel (FACP) indicates a 'Ground Fault' condition.
According to NFPA 72, which type of signal is this, and what is the implication?